Pancreas is an important organ that secretes various digestive enzymes to digest food as well as various hormones to control blood glucose concentration. It is known that functional breakdown of the pancreas due to autoimmune disease, cancer, obesity, or such results in pathological elevation of blood glucose concentration, causing various complications. Diabetes is developed due to deficiency in quantity or deterioration in the function of insulin secreted from β cells present in the pancreas. The therapeutic methods include exercise therapy, diet therapy, oral hypoglycemic agents, and insulin injection. Meanwhile, cell transplantation therapy is performed, in which pancreatic β cells harvested from brain-dead patients are transplanted into diabetes patients. However, the extreme scarcity of donors is problematic in cell transplantation therapy. Recently, transplantation technology has been developed to differentiate pancreatic multipotent progenitor cells to be transplanted from human embryonic stem (ES) cells, and it has drawn attention as a method that solves the donor problem (Kroon E et al., Nat. Biotechnol. (2008) 26(4): 443-52). However, when human ES cell-derived pancreatic progenitor cells are transplanted, only a fraction of the cells differentiated from ES cells differentiate into pancreatic progenitor cells and the remaining cells differentiate into completely different cell populations. Hence, in consideration of safety and efficacy, it is believed to be very important to remove undifferentiated ES cells and to enrich pancreatic multipotent progenitor cells through sorting using specific antibodies. Additionally, conventional technologies cannot distinguish, detect, identify, isolate, and/or obtain pancreatic progenitor cells in a viable state that does not contain foreign genes, proteins, and such; and thus it is desirable to distinguish, detect, identify, isolate, and/or obtain pancreatic progenitor cells in a viable state that do not contain foreign genes, proteins, and such.
By the way, it has been known that the Nephrin-like 3 (Neph3) gene is expressed in central nervous system progenitor cells after division arrest, such as dopamine-producing neuron progenitor cells and GABA-producing inhibitory neuron progenitor cells (WO 2004/038018; WO 2008/096817). However, it is unknown that the gene is relevant to pancreatic multipotent progenitor cells.